Fuse plug and receptacle



April 12 1927. 1,624,030

R. H. WILLIAMS FUSE PLUG AND RECEPTACLE Filed April 6. 1925 INVENTOR R.ZZMLUAMS 744 via.

ATTORNEYS cuit. This block 1 has a receptac Patented pt. 12, 1927.

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Application fled A ril e 1925. Serial No. 21,065.-

is so constructed as to preclude the introduction of a metal conductor such as a' penny, a metal strap or the like, between the lower or central contact of the fuse and the'central contact member of the fuse plug recep- H1018." Thereare many instances wherea person not desiring to purchase anew fuse or replace the fuse when blown resorts to, this method .for securing contlnued supply-- of current. The primary object of my mvention is to prevent this evil.

A further object of my invention is to rovide a fuse plug in which novel means is emplo ed for preventing the use of a 20 ampere guse pin in a'fuse pluinrleceptacle which is intende to receive not g higher than a 15 or 10 ampere fuse.

A further object of my invention is to provide a device ofthe type described which may be installed in the ordinary type of standard fuse plug socket by the replacement of a single contact screw of t he socket.

Other objects and advantages will appear in the following specification, and the novel features of the invention will be articularl pointed out in the appended-c a1m.

y invention 1s illustrated 1n the accomcation, in W eh- I igure 1 is a sectional view of a standard fuse socket showing my improved fuse plug 1 di d therein a ifure 2.is atop plan view of a part of the F co illustrated in Figure 1 3 1s a sectional viewof a part of p the evice shown-in Figure 1, and

Figure 4 is a sectional view of a part er the device illustrated in Flgure 1 shown with L a rtionof the fuse of higher lb carrying out my invention m 0 use of the ordinary type of fuseblock 1, such as found in the standard house liglhting cire portion 2 with insulating material formed integral with the block. A contact shell 3' having rolled threads is disposed'within the receptacle 2 and connected by meansyof a bus stra 4 with a. bindin terminal 5.

The shell 3 is a apted to we the threaded shell of a standard fuse p ug. My

an 'ng dra forming a part of this p 35 gp :3

improved fuse plug 6 has a standard shell 7 which is received-within the shell 3. The fuse plug, is identical inall respects with the standard type of screw socket fuse plu with the exce tion 0 the central termin of the plug w ich as shown at 8 has a depending cylindrical projection 9. The central contact screw of the standard fuse block 1 is removed and a special central contact member forming a part of my invention is substituted therefor. This central contact member consists in a screw, 10 having a flat head 11 irregular in perimetrical contour as shown in dotted lines in Figure 2.

The head 11 is embedded in a disc of insulating material 12. The central contact member is connected by means of the screw portion 10 and a nut 13 thereon to a bus. strap 14 which is in turn connected with the binding screws'15 forming the opposite terminal of-the fuseblock 1. The disc 12 has a'passage 12 having a vertical axis in align: ment with the axis of the screw portion 10. The diameter of the passage is very sli htly larger than the diameter of the cylin rical projection 9 of the central contact 8 of the fuse plug 10, which is intended for use with the contact member 11. I 1

ln Figure 4, I have shown a fuse plug having a central contact member 8 witha cylindrical rojection 9 thereon which is greater in iameter than the projection 9 shown .in Flgure 3. This particular fuse In has a fusible element of greater capaclty than theone associated with the plug shown in Figure 3. e

The disc 12 has a pair of diametrically opposed cavities 16 on the upper face thereof by means of which a two-pronged wrench may be employed to screw t e contact member in place. c. A

From the foregoing description of the various parts of the device, the operation thereof may be readily understood. In Figure '1, I have shown a fuse capacity for use with the se block 1, i. e.,

plllug 6,0f proper the diameter of the member 9 is'sufiiciently small to permit its projection through the passage-12' and contact with the member 11.

Let us assume now that the fusible element withinthe fuse, which is of well known construction, has fused and that a metal conductor, such as a penny 16 (see F re 3) is introduced between the disc 12 an the central contact member of the fuse 6.- The current conducting portions of the central;

contact member are entirely embedded within the disc 12 and exposed onl through the passage 12, thus it is impossib e to establish electrical connection between the central contact member 8 of the fuse lug and the contact member 11 of the blocfi 1.

Let us now assume that a 20 ampere fuse or one of larger capacity than is intended for use with the block 1 is procured. This sage 12.

t is my intention to supply fuses having central contact members with projections 9 of various diameters, the greater the amperage, the greater the diameter of the projection. Likewise for fuse plugs intended for use with a higher are rage, the diam eter of the passage 12' of e central contact prising member disc will increase in proportion to the increase in diameter of the projections 9 of the central contact member 8.

'I- claim:

A device of the character described commember, said contact member having a projection extending therefrom, an enlarged head composed of insulating material for said fuse plug, a receptacle for said fuse plug adapted to be secured to a switch box,

a fuse plug having central contact a central contact member for said receptacle, 7

said contact membeishaving transversely extending prongs forming a cross-shaped head,

and insulating means surrounding said cross-shaped head of the central contact member in said receptacle, except for a space just sufliciently large to permit the introduction of said projection on the fuse plu contact member therethrough, said insu ating means having openings equally spaced between said prongs for permitting the central contact'member of said receptacle to be removed therefrom without the necessity of removing said receptacle from the switch box.

ROY H. WILLIAMS. 

